Circular stapling device with position ribs

ABSTRACT

A circular stapling device includes structure to position an anvil assembly in proper alignment with a cartridge assembly prior to firing of the stapling device. The stapling device includes an anvil assembly, a cartridge assembly including a staple cartridge and shell housing, and an anvil retainer that has a proximal portion including a longitudinal rib and a distal portion including at least one second longitudinal rib. The first longitudinal rib is received within a slot formed within the shell housing to prevent rotation of the anvil retainer in relation to the shell housing. The at least one second longitudinal rib is received within a longitudinal channel of the anvil assembly to prevent rotation of the anvil assembly in relation to the anvil retainer. The presently disclosed structure obviates the need for splines and the disadvantages associated with the use of splines.

BACKGROUND 1. Technical Description

The present disclosure is directed to circular stapling devices, and more particularly, to circular stapling devices including structure to properly align an anvil assembly with a staple cartridge of a shell assembly of the circular stapling device.

2. Background of Related Art

Circular stapling devices are utilized by clinicians to apply one or more surgical fasteners, e.g., staples or two-part fasteners, to body tissue for the purpose of joining segments of body tissue together and/or for the creation of an anastomosis. Circular stapling devices generally include a cartridge or shell assembly supporting a plurality of annular rows of staples, an anvil assembly operatively associated with the cartridge assembly and having annular arrays of staple receiving pockets for providing a surface against which the plurality of annular rows of staples can be formed, and an annular blade for cutting tissue.

During a typical tissue fastening procedure, the anvil assembly of the stapling device is positioned within one segment of body tissue and the shell assembly and a body portion of the stapling device supporting the shell assembly are positioned in an adjacent segment of body tissue. The anvil assembly is then attached to the body portion of the stapling device and the stapling device is actuated to approximate the anvil assembly with the cartridge assembly and clamp the body tissue segments together.

Typically, the anvil assembly includes an anvil shaft that includes splines that mate with splines formed within a shell housing of the shell assembly to align the staple forming pockets of the anvil assembly with staple receiving pockets of the staple cartridge of the shell assembly. Misalignment of the splines often results in misalignment of the staple forming pockets of the anvil assembly and the staple receiving pockets of the shell assembly such that malformation of the staples occurs during firing of the stapling device.

A continuing need exist for a circular stapling device including more reliable alignment structure for aligning the staple forming pockets of the anvil assembly with the staple receiving pockets of the shell assembly.

SUMMARY

In one aspect of the disclosure, a surgical stapling device includes a body portion and a tool assembly supported on a distal portion of the body portion. The tool assembly includes an anvil assembly and a cartridge assembly. The body portion includes an anvil retainer having a proximal portion and a distal portion. The proximal portion of the anvil retainer supports a first longitudinal rib and the distal portion of the anvil retainer supports a second longitudinal rib. The anvil assembly of the tool assembly has an anvil shaft and an anvil head supported on a distal portion of the anvil shaft. The anvil shaft has a plurality of resilient legs defining a bore. The resilient legs flex outwardly to facilitate passage of the anvil retainer into the bore. Adjacent resilient legs of the plurality of resilient legs define longitudinal channels. At least one of the longitudinal channels defined by the resilient legs receives the second longitudinal rib to prevent rotation of the anvil shaft in relation to the anvil retainer. The shell assembly is supported on a distal portion of the body portion and includes a shell housing having an inner housing portion defining a through bore. The anvil retainer extends through the through bore. A bushing is supported within the through bore of the inner housing portion of the shell housing. The bushing defines an internal slot that receives the first longitudinal rib to prevent rotation of the anvil retainer within the through bore of the bushing.

In another aspect of the disclosure, the surgical stapling device includes a body portion, an anvil assembly, and a cartridge assembly. The body portion includes an anvil retainer, having a proximal portion supporting a first longitudinal rib and a distal portion supporting at least one second longitudinal rib. The anvil assembly has an anvil shaft and an anvil head supported on a distal portion of the anvil shaft. The anvil shaft defines a longitudinal bore and at least one longitudinal channel. The longitudinal bore is dimensioned to receive the distal portion of the anvil retainer. The second longitudinal rib is received within the at least one longitudinal channel when the distal portion of the anvil retainer is received within the longitudinal bore to prevent rotation of the anvil assembly in relation to the anvil retainer. The shell assembly is supported on a distal portion of the body portion and includes a shell housing having an inner housing portion defining a through bore. The anvil retainer extends through the through bore. A bushing defining an internal slot is supported within the through bore of the inner housing portion of the shell housing. The internal slot receives the first longitudinal rib of the anvil retainer to prevent rotation of the anvil retainer within the through bore of the bushing.

In embodiments, the bushing includes an external slot and the inner housing portion includes an inner wall that defines the through bore. The inner wall of the inner housing portion supports a third longitudinal rib that is received within the external slot of the bushing to prevent rotation of the bushing within the through bore of the inner housing portion.

In some embodiments, the distal portion of the anvil retainer supports a plurality of second longitudinal ribs, wherein each of the plurality of second longitudinal ribs is received within a respective one of the longitudinal channels defined between the resilient legs of the anvil shaft.

In certain embodiments, the bushing is formed from a metal.

In embodiments, the stapling device includes a handle assembly and the body portion extends distally from the handle assembly.

In some embodiments, the shell assembly is releasably coupled to the body portion.

In certain embodiments, a distal portion of the bushing is formed with spaced rings that are positioned to engage the inner wall of the inner housing portion of the shell housing within the through bore to secure the bushing within the through bore.

In embodiments, the anvil head is pivotally supported on the anvil shaft.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the presently disclosed surgical stapling device are described herein below with reference to the drawings, wherein:

FIG. 1 is a side perspective view of an exemplary embodiment of the presently disclosed surgical stapling device with a tool assembly in an unclamped position;

FIG. 2 is a side perspective view of the surgical stapling device shown in FIG. 1 with the tool assembly separated from the remaining portion of the stapling device;

FIG. 3 is a perspective view from a distal end of a “Prior Art” surgical stapling device with an anvil assembly of a tool assembly of the surgical stapling device separated from the surgical stapling device;

FIG. 4 is a side perspective view of the tool assembly and anvil retainer of the surgical stapling device shown in FIG. 1 with the tool assembly in an unclamped position and a body of the surgical stapling device shown in phantom;

FIG. 5 is an exploded view of the tool assembly and anvil retainer shown in FIG. 4;

FIG. 6 is a cross-sectional view taken along section line 6-6 of FIG. 4;

FIG. 7 is a side perspective view from a proximal end of the shell assembly of the tool assembly shown in FIG. 5 with a bearing member removed;

FIG. 8 is a side perspective view from the proximal end of the shell assembly of the tool assembly shown in FIG. 7 with the bearing member attached to the shell housing;

FIG. 9 is a cross-sectional view taken along section line 9-9 of FIG. 8;

FIG. 10 is a side perspective view of the anvil retainer of the surgical stapling device shown in FIG. 2;

FIG. 11 is a side perspective view from the proximal end of the shell assembly of the tool assembly shown in FIG. 7 with the bearing member attached to the shell housing and the anvil assembly extending through the shell assembly in a retracted position;

FIG. 12 is a cross-sectional view taken along section line 12-12 of FIG. 11;

FIG. 13 is a side perspective view of the anvil assembly and anvil retainer of the surgical stapling device shown in FIG. 1; and

FIG. 14 is a cross-sectional view taken along section line 14-14 of FIG. 13.

DETAILED DESCRIPTION OF EMBODIMENTS

The presently disclosed surgical stapling device will now be described in detail with reference to the drawings in which like reference numerals designate identical or corresponding elements in each of the several views. In this description, the term “proximal” is used generally to refer to that portion of the device that is closer to a clinician, while the term “distal” is used generally to refer to that portion of the device that is farther from the clinician. In addition, the term “endoscopic” is used generally used to refer to endoscopic, laparoscopic, arthroscopic, and/or any other procedure conducted through small diameter incision or cannula. In addition, the term clinician is used generally to refer to medical personnel including doctors, nurses, and support personnel.

The presently disclosed circular stapling device includes structure to position an anvil assembly in alignment with a cartridge assembly prior to firing of the stapling device. The stapling device includes an anvil assembly, a cartridge assembly including a staple cartridge and shell housing, and an anvil retainer that has a proximal portion including a longitudinal rib and a distal portion including at least one second longitudinal rib. The first longitudinal rib of the anvil retainer is received within a slot formed within the shell housing of the cartridge assembly to prevent rotation of the anvil retainer in relation to the shell housing. The at least one second longitudinal rib of the anvil retainer is received within a longitudinal channel of the anvil assembly to prevent rotation of the anvil assembly in relation to the anvil retainer. The presently disclosed structure obviates the need for splines and the disadvantages associated the use of splines.

Referring to FIGS. 1 and 2, the presently disclosed surgical stapling device shown generally as 10 includes a handle assembly 12, an elongated body portion 14 that extends distally from the handle assembly 12, and a tool assembly 16 that is supported on a distal portion of the elongated body portion 14. The tool assembly 16 includes an anvil assembly 20 and a cartridge or shell assembly 18 that supports a staple cartridge 18 a. The handle assembly 12 includes an approximation knob 22 that operates an approximation mechanism (not shown) to move the anvil assembly 20 in relation to the cartridge assembly 18 between unclamped and clamped positions, and a firing trigger 24 that that operates a firing mechanism (not shown) to fire staples (not shown) from the staple cartridge 18 a into tissue. For a detailed description of an exemplary circular stapling device including known approximation and firing mechanisms, see U.S. Pat. No. 7,857,187 (“the '187 Patent”) which is incorporated herein by reference in its entirety.

Although the presently disclosed stapling device 10 is shown and described as being a manually powered device, it is envisioned that the stapling device 10 can be an electrically powered device such as described in U.S. Patent Publication No. 2012/0253329 which is incorporated herein by reference in its entirety.

The staple cartridge 18 a of the shell assembly 18 has an annular configuration and the anvil assembly 20 includes an anvil 20 a (FIG. 5) having an annular configuration. The anvil assembly 20 is supported on an anvil retainer 30 which forms part of the approximation mechanism (not shown) of the stapling device 10 and is configured to releasably engage the anvil assembly 20. The anvil retainer 30 includes a distal portion that extends from a distal end of the elongate body portion 14 of the stapling device 10 and through the shell assembly 18 to a position to engage the anvil assembly 20 and a proximal portion that is operatively connected to the approximation knob 22 such that rotation of the approximation knob 22 causes the anvil assembly 20 to move in relation to the staple cartridge 18 a of the shell assembly 18 between an unclamped or spaced position and a clamped position. The shell assembly 18 includes an annular knife 28 (FIG. 1) that is movable from a retracted position to an advanced position within the shell assembly 18 during firing of the stapling device 10 to transect tissue clamped between the staple cartridge 18 a and the anvil 20 a.

The shell assembly 18 is releasably coupled to a distal portion of the elongated body 14 of the stapling device 10 to facilitate replacement of the shell assembly 18 after each use. Mechanisms for releasably coupling the shell assembly 18 to the elongate body portion 14 of the stapling device 10 are described in U.S. Patent Publication Nos. 2016/0310141, 2016/0192938, and 2016/0192934 which are incorporated herein in their entirety by reference.

Referring to FIG. 3, in “Prior Art” circular stapling devices 100, the anvil assembly 120 includes an anvil head 122 and an anvil shaft 124, and the shell assembly 118 includes a staple cartridge 125 and a shell housing 126 having an inner housing portion 128 that defines a through bore 128 a. The anvil retainer 130 is received within the through bore 128 a and is movable between retracted and advanced positions. When the anvil shaft 124 is coupled to the anvil retainer 130 and the anvil retainer 130 is retracted (via actuation of the approximation knob 22, FIG. 1), the anvil shaft 124 is drawn into the through bore 128 a of the inner housing portion 128 of the shell housing 126. In order to properly align the anvil head 122 of the anvil assembly 120 with the staple cartridge 125 of the shell assembly 118, the anvil shaft 124 includes splines 134 that are received between splines 136 formed along an inner wall of the inner housing portion 128 of the shell housing 126. Receipt of the splines 134 of the anvil shaft 124 between the splines 136 of the shell housing 126 causes rotation of the anvil head 122 of the anvil assembly 120 in relation to the staple cartridge 125 of the shell assembly 118 to properly align the staple cartridge 125 with the anvil head 124 during approximation of the anvil assembly 120 and the shell assembly 118. As discussed briefly above, occasionally, the splines 134 and 136 crash or bind with each other and proper alignment between the anvil assembly 120 and the shell assembly 118 is not achieved. Such crashing and/or binding may result in improper staple formation or locking of the stapling device 100.

Referring to FIGS. 4-6, as discussed above, the tool assembly 16 of the presently disclosed stapling device 10 (FIG. 1) includes a shell assembly 18 and an anvil assembly 20. The shell assembly 18 includes a shell housing 36 that supports the staple cartridge 18 a and a pusher 38 (FIG. 6). The shell housing 36 includes an inner housing portion 40 (FIG. 6) that defines a through bore 42. The anvil assembly 20 includes an anvil shaft 44 and an anvil head 46 that is supported on a distal portion of the anvil shaft 44. In embodiments, the anvil head 46 is pivotally supported on the anvil shaft 44 and is urged to a tilted position by a biasing mechanism 48. The pivotal anvil head 46 and biasing mechanism 48 are known in the art and do not form part of the improvements disclosed in this application. U.S. Pat. Nos. 9,492,168 and 8,540,132 disclose exemplary pivotal anvil assemblies and biasing mechanisms and are incorporated herein by reference in their entirety.

In embodiments, the through bore 42 (FIG. 6) of the inner housing portion 40 of the shell housing 36 includes a proximal portion 50 having an increased diameter defining a step 52 between a distal portion of the through bore 42 and the proximal portion 50. The shell assembly 18 includes a substantially cylindrical bushing 60 that is received in the proximal portion 50 of the through bore 42. The bushing 60 defines a through bore 62 that is coaxial with the through bore 42 of the inner housing portion 40 of the shell housing 36. In embodiments, the bushing 60 defines an external slot 64 and an internal slot 66 which will be described in further detail below. In some embodiments, the distal portion of the bushing 60 is formed with spaced rings 68 that are dimensioned to engage an inner wall of the inner housing portion 40 of the shell housing 36 to secure the bushing 60 within the proximal portion 50 of the through bore 42. Alternately, other coupling methods or devices can be used to secure the bushing 60 within the inner housing portion 40 of the shell housing 36. In some embodiments, the bushing 60 is formed from a rigid, high strength material such as a metal, e.g., stainless steel. U.S. Pat. No. 9,492,168 (“the '168 Patent”) which is incorporated herein by reference in its entirety.

The anvil assembly 20 includes the anvil shaft 44 and the anvil head 46 which is supported on the distal portion of the anvil shaft 44. In embodiments, the anvil shaft 44 includes a proximal portion having a plurality of resilient legs 70 that define a bore 72. The resilient legs 70 are spaced from each other to define longitudinal channels 70 a between adjacent resilient legs 70. The bore 72 is dimensioned to receive the anvil retainer 30 to releasably secure the anvil shaft 44 to the anvil retainer 30. An inner wall 74 of each of the resilient legs 70 defines a recess 76 that defines a shoulder 76 a. The recess 76 receives an abutment 78 formed on an outer surface of the anvil retainer 30 as is known in the art to secure a distal portion of the anvil retainer 30 within the bore 72 of the anvil shaft 44. See, e.g., the '168 Patent.

The anvil retainer 30 is secured to a distal portion of an approximation mechanism (not shown) and is advanced or retracted within the through bore 42 of the inner housing portion 40 of the shell housing 36 by rotating the approximation knob 22 (FIG. 1). In embodiments, the anvil retainer 30 includes a distal portion 80 that defines a trocar 82 having a tapered distal end and a larger diameter proximal portion 84 that is received within the through bore 42 of the inner housing portion 40 of the shell housing 36 and is secured to the approximation mechanism (not shown) of the surgical stapling device. In embodiments, the proximal portion 84 (FIG. 5) of the anvil retainer 30 supports a longitudinally extending first rib 86 and the distal portion 80 of the anvil retainer 30 includes at least one second rib 88. In embodiments, the at least one second rib 88 includes two ribs 88.

When the anvil assembly 20 is coupled to the anvil retainer 30, the distal portion of the anvil retainer 30 is inserted into an opening 90 (FIG. 5) defined at a proximal end of the resilient legs 70. When the abutment 78 formed on an outer surface of the anvil retainer 30 engages the resilient legs 70, the resilient legs 70 flex outwardly to facilitate further passage of the anvil retainer 30 into the anvil shaft 44. When the abutment 78 is moved into alignment with the recess 76 (FIG. 6), the resilient legs 70 flex inwardly such that the abutment 78 is received within the recess 76 and the anvil assembly 20 is releasably secured to the anvil retainer 30. The abutment 78 defines a shoulder 78 a that engages the shoulder 76 a defining the recess 76 to resist separation of the anvil assembly 20 from the anvil retainer 30.

Referring also to FIGS. 7-9, the inner housing portion 40 of the shell housing 36 includes an inner wall 92 that defines the through bore 42 of the inner housing portion 40. The inner wall 92 supports a longitudinal rib 94. When the bushing 60 is secured within the through bore 42 (FIG. 9) of the inner housing portion 40 of the shell housing 36, the longitudinal rib 94 is received within the external slot 64 defined in the distal portion of the bushing 60 (FIG. 9). Placement of the longitudinal rib 94 within the external slot 64 of the bushing 60 prevents the bushing 60 from rotating within the inner housing portion 40 of the shell housing 36.

Referring to FIGS. 10-12, as discussed above, the through bore 62 of the bushing 60 defines an internal slot 66 (FIG. 12). When the anvil retainer 30 is received within the through bore 62 of the bushing 60, the longitudinally extending first rib 86 formed on the proximal portion 84 of the anvil retainer 30 is received within the internal slot 66 of the bushing 60. Placement of the longitudinally extending first rib 86 within the internal slot 66 of the bushing 60 prevents the anvil retainer 30 from rotating within the bushing 60.

Referring to FIGS. 13 and 14, as the anvil retainer 30 is slid into the bore 72 (FIG. 5) of the anvil shaft 44, the longitudinally extending second ribs 88 formed on the distal portion 80 of the anvil retainer 30 are received in the respective longitudinal channels 70 a defined between the resilient legs 70 of the anvil shaft 44. Receipt of the longitudinally extending second ribs 88 within the channels 70 a defined between the resilient legs 70 prevents rotation of the anvil assembly 20 in relation to the anvil retainer 30.

In the presently disclosed stapling device 10, the anvil shaft 44 of the anvil assembly 20 does not include splines. Relative rotation between the anvil head 46 of the anvil assembly 20 and the staple cartridge 18 a of the shell assembly 18 is prevented by including first and second longitudinal ribs 86, 88 on the anvil retainer 30 to prevent rotation of the anvil retainer 30 in relation to the shell housing 36 and to prevent rotation of the anvil assembly 20 in relation to the anvil retainer 30.

Persons skilled in the art will understand that the devices and methods specifically described herein and illustrated in the accompanying drawings are non-limiting exemplary embodiments. It is envisioned that the elements and features illustrated or described in connection with one exemplary embodiment may be combined with the elements and features of another without departing from the scope of the present disclosure. As well, one skilled in the art will appreciate further features and advantages of the disclosure based on the above-described embodiments. Accordingly, the disclosure is not to be limited by what has been particularly shown and described, except as indicated by the appended claims. 

What is claimed is:
 1. A surgical stapling device comprising: a body portion including an anvil retainer, the anvil retainer having a proximal portion and a distal portion, the proximal portion supporting a first longitudinal rib and the distal portion supporting a second longitudinal rib; an anvil assembly having an anvil shaft and an anvil head supported on a distal portion of the anvil shaft, the anvil shaft having a plurality of resilient legs defining a bore, the resilient legs being flexible outwardly to facilitate passage of the anvil retainer into the bore, adjacent resilient legs of the plurality of resilient legs defining longitudinal channels, at least one of the longitudinal channels defined by the resilient legs receiving the second longitudinal rib to prevent rotation of the anvil shaft in relation to the anvil retainer; a shell assembly supported on a distal portion of the body portion, the shell assembly including a shell housing having an inner housing portion defining a through bore, the anvil retainer extending through the through bore; and a bushing supported within the through bore of the inner housing portion of the shell housing, the bushing defining an internal slot, wherein the internal slot receives the first longitudinal rib to prevent rotation of the anvil retainer within the through bore of the bushing.
 2. The surgical stapling device of claim 1, wherein the bushing includes an external slot, and the inner housing portion includes an inner wall that defines the through bore, the inner wall of the inner housing portion supporting a third longitudinal rib, the third longitudinal rib being received within the external slot of the bushing to prevent rotation of the bushing within the through bore of the inner housing portion.
 3. The surgical stapling device of claim 2, wherein a distal portion of the bushing is formed with spaced rings, the spaced rings being positioned to engage the inner wall of the inner housing portion of the shell housing within the through bore to secure the bushing within the through bore.
 4. The surgical stapling device of claim 1, wherein the distal portion of the anvil retainer supports a plurality of second longitudinal ribs, wherein each of the plurality of second longitudinal ribs is received within a respective one of the longitudinal channels defined between the resilient legs of the anvil shaft.
 5. The surgical stapling device of claim 1, wherein the bushing is formed from a metal.
 6. The surgical stapling device of claim 1, further including a handle assembly, the body portion extending distally from the handle assembly.
 7. The surgical stapling device of claim 1, wherein the shell assembly is releasably coupled to the body portion.
 8. The surgical stapling device of claim 1, wherein the anvil head is pivotally supported on the anvil shaft.
 9. A surgical stapling device comprising: a body portion including an anvil retainer, the anvil retainer having a proximal portion supporting a first longitudinal rib and a distal portion supporting at least one second longitudinal rib; an anvil assembly having an anvil shaft and an anvil head supported on a distal portion of the anvil shaft, the anvil shaft defining a longitudinal bore and at least one longitudinal channel, the longitudinal bore being dimensioned to receive the distal portion of the anvil retainer, wherein the second longitudinal rib is received within the at least one longitudinal channel when the distal portion of the anvil retainer is received within the longitudinal bore to prevent rotation of the anvil assembly in relation to the anvil retainer; a shell assembly supported on a distal portion of the body portion, the shell assembly including a shell housing having an inner housing portion defining a through bore, wherein the anvil retainer extends through the through bore; and a bushing supported within the through bore of the inner housing portion of the shell housing, the bushing defining an internal slot, wherein the internal slot receives the first longitudinal rib of the anvil retainer to prevent rotation of the anvil retainer within the through bore of the bushing.
 10. The surgical stapling device of claim 9, wherein the bushing includes an external slot and the inner housing portion includes an inner wall that defines the through bore, the inner wall of the inner housing portion supporting a third longitudinal rib, the third longitudinal rib being received within the external slot of the bushing to prevent rotation of the bushing within the through bore of the inner housing portion.
 11. The surgical stapling device of claim 9, wherein the distal portion of the anvil retainer supports a plurality of second longitudinal ribs, each of the plurality of second longitudinal ribs being received within a respective one of the at least one longitudinal channel defined between the resilient legs of the anvil shaft.
 12. The surgical stapling device of claim 9, wherein the bushing is formed from a metal.
 13. The surgical stapling device of claim 9, further including a handle assembly, the body portion extending distally from the handle assembly.
 14. The surgical stapling device of claim 9, wherein the shell assembly is releasably coupled to the body portion.
 15. The surgical stapling device of claim 10, wherein a distal portion of the bushing is formed with spaced rings, the spaced rings being positioned to engage the inner wall of the inner housing portion within the through bore to secure the bushing within the through bore.
 16. The surgical stapling device of claim 9, wherein the anvil head is pivotally supported on the anvil shaft. 